Start with BiggerPockets Ultimate Beginners Guide (free).

Above that income level the rate climbs to 20 percent.But ultimately it’s  personal decision, loaded with plus and minuses. let us know what you decide to do!

Here are a few I recommend: "Rich Dad, Poor Dad" by Roberto Kiyosaki; "Set for Life" by Scott Trench; "The Unofficial Guide to Real Estate Investing" by Spencer; "The BiggerPockets Ultimate Beginners Guide" found here on BP; "The Book on Rental Property Investing" by Brandon Tuner.

Ultimately, it is up to the owners to figure out how they want to structure things.

The cost of UDFI is generally nominal, and should erase only a small fraction of the boost in return that the use of leverage creates.So:  Make an all cash purchase and receive 10% return or make a leveraged purchase, pay tax on UDFI, and make 13% return. 

The problem with this is that they tend to place INCOME as the main feature of any investment they’re currently considering, and their decision making process centers around how a particular investment will fit into their ULTIMATE portfolio, the one that is large enough to generate all that income which will replace their earnings, and still grow enough to offset inflation.In my opinion, what the investor in this situation should be doing is concentrating on WEALTH BUILDING, not passive income.  

@Daniel Stoychev ultimately, Chicago is such a large market that I tell folks to start where you know.

unless you understand the actual DSCR, lender finance , there is no such thing as Great GP.Great GP that works in 2018 ultimately many failed in 2023 There's difference between actual marketing pitch, and actual apartment condition in practice. 

This, the same as any other business, comes directly from revenue which ultimately comes from you the client. 

I no longer qualified for traditional financing because I already own many rental properties and my DTI was high for the bank, so I purchased these in a business entity with a trusted private investor and was able to refi the 1st property/sell the 2nd property to pay back my investor and ultimately keep the better property for zero money down.